It went from floral visitor to spider prey to spider dinner when it made a single solitary mistake: it inadvertently fell into a sticky web.

Its life-and-death struggle in our back yard did not escape a trio of cellar spiders (family Pholcidae). They rapidly descended on the squirming fly.

This was the first time I've ever seen cellar spiders hunt together. While one wrapped it in silk for future dining pleasure, another administered a fatal bite. The powerful poison paralyzed it. Then one of the bigger spiders tugged the wrapped prey under the lip of our barbecue table. Out of sight.

Bon appetit! Table for three!

It's not easy identifying "what's for dinner" but Martin Hauser, a senior insect biosystematist with the Plant Pest Diagnostics Branch, California Department of Food and Agriculture, said it's definitely a Tachinid fly. There are hundreds of Tachinidae genera, he says, but this one is very likely a Peleteria.

I'm just glad the catch of the day wasn't a honey bee.

Two cellar spiders work together to capture a Tachinid fly in their web. (Photo by Kathy Keatley Garvey)

While one spider wraps the fly, another bites it in the head, paralyzing it. (Photo by Kathy Keatley Garvey)